Resistance



June 17, 1930. J, GELOSO 1,763,772

RESISTANCE Filed Sept. 27, 1927 a i INVENTOR BY a M A'ITORNE umrso STATES,

PATENT OFFICE;

IOEI enoso, or m YORK, n. 1., assrenon, n mam assreum'rs, 'ro :rILo'r name, a rm comm-non, or nnooxnnr, rmw YORK, a conrona'non or nmwm u'srsrucn Application ma member 31, 1927. Serial no; man.

This invention relates to improvements in resistance elements, particularly those appliedin wer units including A, B and C battery tors. 1

At the present time the resistances used in power'umts and comprising usually of an insulated core generally formed of porcelain are composed of a' continuous length of resistance wire pomtioned so that the turns are closely adjacent one another and have co- .0 therewith movable conductors, w liib h nductors in the form of rings are of such width that a considerable number of turns of wire are contacted thereby at all times.

In changing the resistance of the element in conjunction with the remaining part of the power unit, considerable difiiculty is encountered in obtaining accurate settings and so duplicate settings, in view of the fact that a slight movement in either direction of the conducting band will cause a considerable variation in the resistivity of the element, due to the extremely large number of turns of wire traversed upon even the slightest displacement or deviation of the conducting bandor ring along the length of the resistance element.

To ofi'set this difliculty the applicant has so provided a novel form of resistance element comprising of a length of wire having alternate closely or densely wound and sparsely wound sections, the closely wound sections of considerably greater density per unit of length and of larger extent, while the sparsely woundportions are approximately one-tenth as dense, or less, per unit len h. In this type of resistance the dense sections of the wire, naturally, are the areas of high resistivity, while the sparsely wound sections are of comparatively negligible resistivity,- for the necesyet, at the same time prov1 sary conductivity from the ensely wound wire sections through the contact band and into the remaining part of the f power unit circuit.

The densely wound this resistance element are so constructed as to provide for a definite resistance value, controllable and calibrated as to their amount merely by,

the amount of winding thereon, but each se arable by a sparsely wound section of wire, w ch sparsely wound section of wire is adapted to have contacted therewith the conducting band so that the resistance of a densely wound portion between two of the sparsely wound sections can be accurately called that only of the 'denselyzwound section. v

Broadly, then, this invention contemplates the intr notion of a variable resistance element for power units in which alternate sections of continuous resistance wire are com- I of densely wound sections, while the interconnecting portions are sparsely wound,

upon whichsparsely wound sections there are adapted to be positioned into conductive relation therewith contact wires whereby the active resistance is that of the dense section of wire between the conductin bands ositioned in contact with the sparse y woun sections'of the wire.

Specifically it is aimed to-provide a resistance element capable of introducing varying amounts of resistance in a power or any other radio circuit, which resistance element is characterized by the novel feature therein of low resistance sections adjacent high resistance sections, so that movable conductors resting on the low resistance section adscent high resistance section, will allow or the introduction of a resistance in the circuit of exactly the amount calibrated as the value for the'hlghresistance.

These and other advantages, 0 abilities, and features of the invention will ap ar from the subjoined detail descri tion 0 one specific embodiment therefor i ustrated in the accompanying drawings, in which,

Fig. 1 is a side elevation of the resistance element.

Fig. '2 is a view partly in section taken along lines 22 of Fig. 1. a

Fig. 3 is a front viewin section taken along lines 33 of Fi 1.

Referring to the reference characters in the drawing, numeral 10 represents the core of the resistance element comprising of a noninsulating material such as porcelain or ceramic material, having a central aperture 11 nates at opposite extremities of the core 10,

being adapted to form a contact not shown with the contact rin 12 which have terminal posts 13 thereon for Interconnection of the resistance element to the remaining parts of the radio circuit.

As shown in Fig. 3 this contact ring 12 is split at its upper extremity having its two portions 14. and 15 fastened y means of a bolt 16. Since the contact ring 12 is formed of flexible copper or brass plate, the contact ring me be adapted to be compressed or expande wit respect to the core element 10 or to the wire thereon by mere operation of the bolt 16 fastening the two ortions 14 and 15 thereof, a loosenin of the bolt being adapted to cause an expansion of the ring and to allow the said ring to he passed along the length of the core 10 to contact with the wire at any required portion thereof; the contact ring being of higher conductivity, naturally, the resistance of the wire will be that resistance only between any twoyof the contact rings.

As shown in Fig. 1 the resistance wire is wound alternately into densely wound sections 17 and very sparsely wound sections 18, it being the purpose of this invention to cause the contact rings to be positioned on the core only at the sparsely wound sections 18 thereof so that the small amount of resistance wire which contacts with the inner face of the contact ring 12 will be infinitely small and negligihle in comparison to the resistance introuced upon passage of current through the dense winding of the sections 17 Since the contact ring 12 is narrower than the sparsely wound resistance section 18, the ring will never contact with any of the windings of the densely wound section 17, and the resistance which will be obtained between any two contact rings positioned in the sparsely wound sections, will be that of the densely wound sections therebetween.

As seen in Fig. 1 the respective densely wound sections 17 of resistance are of variable length, each section being sufiicient for the introduction of the required resistance in the circuit, so that the contact rings will be usually placed in the sparsely wound sections 18 on opposite sides of a densely wound section 17 but it is obvious from the disclosure, that even if a still higher resistance were required, and the two contact rings should be placed at opposite sides of a series of two or more of t e densely wound resistances as shown in Fig. 1, the resistance resulting from the sparsely wound sections will be so small in comparison with that introduced by the densely wound sections, that the required resistance can be considered to be that of the sections 19 on op densel wound sections alone, the deviations 'of the device wherein a p urality of rings 12 and 12 are positioned in the sparsely wound site sides of a densely wound section 20, t e resistance of the sparsely wound sections being negligible, in fact, approaching zero, while the fact that the extremities of the conducting rings Hand 12 are positioned at a fraction of an inch from the extremities of the densely wound section 20, will allow for the introduction, upon passage of current therethrough, of the calibrat-' ed value of the resistance of the dense sec tion 20.

Though the core element herein has been shown as a hollow cylinder, it is within the province of the invention to provide for shape or size of resistance element, as long as the wire is positioned in alternately densely wound and sparsely wound sections, and the conductor bands or rings are disposed within the sparsely wound sections.

'It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims.

What I claim is:

1. A resistance element comprising a length of wire formed as a plurahty of sections of sparsely wound and densely wound wire turns, contact rings slidable over said sections of wire and adapted to be positioned on the sparsely wound sections whereby the resistance formed by the passage of current from one contact ring through the resistance and through the second contact ring is that of the densely wound section.

2. A resistance element com rising a core having a continuous length 0' wire wound thereon, said wire being composed of a plurality of sparsely wound and densely wound sections alternately disposed along the length of the core and conductor members comprising movable bands slidable along said core over said wire and adapted to rest in the sparsely wound wire sections, whereby the resistance formed by the p of current from one contact hand through the resistance and through the second contact band is equal to the resistance of the densely wound section of wire.

3. A resistance element comprising an insuilating core havingwire wound thereon in alternatel densely and sparseliynwound sections, con uctor bands surroun g said wire and movable along the core, said bands being adapted to rest and be in contact with the sparsely wound sections of the resistance wire whereby the resistance produced upon passage of current through said conductor bands is equal to the resistance of the densely wound wire positioned between the conducting bands.

4. A resistance element comprising an insulating core having a length of resistance wire wound thereon in alternately densely and sparsely wound sections, the densely wound sections comprising a considerably greater amount of turns than the sparsely wound sections, conductors slidable over said wire along said core element and adapted to rest in the sparsely wound sections on opposite sides of a densely wound section, whereby the resistance introduced upon passage of current therethrough' is equal to the resistance of the densely wound section. 5. A resistance element, comprising an insulated core, having a length of resistance wire Wound thereon in alternate densely and sparsely wound sections, conductors slidable over said'wlre, along said core and adapted to rest in the sparsely wound sections, said densely wound sections of wire being of different lengths, whereby to introduce varying resistances between conductors positioned in thespa'rsely wound sections of wire.

6. A resistance element, comprising a length of wire, formed as a lurality of sections of alternate sparsely ans densely wound series of turns of wire, conductor bands contacting with said sparsely wound turn series,

the resistance of the sparsel wound turn series bein negligible, said ensely wound turn series eing com osed of different numbers of turns, where y variation in the resistance of the element'may be provided for by the displacement into different 5 arsely wound sections along the length of t e element of the conductor bands.

. JOHN GELOSO. 

